Disadvantage in early childhood poses multiple risks to children's development. Factors such as low socioeconomic status, long-term unemployment of parents, and social isolation may have lasting impressions,impacts,affects,variationson a child's chance of reaching their full potential. Whilst not eliminating disadvantage, preschool education can help to lessen,hold,hoist,enlargethe effects of these risk factors and can provide children with a better start to school. However, some of these factors may also be barriers,roundabouts,accesses,assessmentsto preschool attendance for groups that would benefit most from preschool education. In Australia, the early years of children's education is the responsibility of many government and non-government agencies and it occurs in a range of settings. Preschool is aimed at children around four years of age to undo,fix,tie,preparethem for compulsory schooling from the age of six years. In most states and territories, children can start full-time schooling at five years of age, when they enrol in a kindergarten or preparatory year. In 2001, just over half of five-year olds (57%) were at school with about a third (34%) attending preschool. While in some states and territories children can commence,alter,delay,escapepreschool before they turn four, participation rates for three-year olds are much lower than four-year olds (24% compared with 56% for four-year olds in 2001). The preschool participation rate of four-year olds in 2001 (56%) was similar to the rate in 1991 (58%).